Weirdest issue with ventrilo, skype, and the like - scheduled inbound lag for 2+ hrs.

It's been driving me crazy. It started only three or so weeks ago. A summary of the issue is as follows: around 6PM Pacific Standard Time, every single night (so far as I've been able to track and experience), I'll be on ventrilo with friends, and suddenly they will start to cut out. I'll watch their speaker icons stay green as if they're speaking with an open mic, but in reality, it's just lag on my side somehow. "Ping" as displayed on the ventrilo application will erratically change every ten to fifteen seconds or so anywhere from 200ms to 30,000ms. All the while, traceroute, ping, etc., all these will return pings under 200 while this is happening. Outbound is fine, there is no upload lag whatsoever, no lag in the game, closing the game doesn't help (WoW in case you're wondering). Skype experiences similar inbound lag. This will all last until about 8PM PST, give or take, but mostly give.

So, it's not a network problem as far as I can prove, yet it's entirely network related. It's mindblowing. Sadly, I'm a guild leader on the game I play, and I run rated games, so it's very important that this works for me, but it only starts right around the time that I can schedule these games. My ISP absolutely will not help me with this as I cannot show them via ping tests that it's their problem. I'm afraid it may not be.

My CPU during this time seems okay. I can't really find any red flags. I haven't really installed any new widgets or anything that I can think of. I've tried quitting various processes during all this, like relaunching finder, quitting iTunes, Safari, even WoW, and even just trial and error through the activity monitor - no luck.

I tried running sudo tcpdump in the terminal and I really have no idea how to read it, not too seasoned in network analysis... But I will attach a picture. I know it doesn't help that you can't see my IP address, but I am kinda paranoid about posting it, too.

Anyway, any help would be a blessing. Thanks.

Picture 11.png is the tcpdump and activity monitor. 22 and 21 is a full list of running processes.

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